The present invention relates to a light irradiating device, manufacturing method thereof and lighting apparatus using the light irradiating device, more particularly, the technology of achieving the improvement in the light irradiation efficiency and the improvement in the reliability of the device.
First, in case the light must be irradiated in great quantities, normally the electric lamp, etc. are employed. However, for the purpose of the reduction in weight, thickness, and size and the saving of electricity, sometimes the light emitting elements 2 are mounted on the printed circuit board 1, as showing FIG. 21.
The light emitting diode formed of the semiconductor is mainly employed as this light emitting element. But the semiconductor laser, etc. may also be employed.
The light emitting diode 2 has two leads 3, 4. One lead 3 is adhered to the back surface of the light emitting diode chip 5 (the anode electrode or the cathode electrode) with the solder, etc., while the other lead 4 is electrically connected to the electrode on the chip surface (the cathode electrode or the anode electrode) via the metal thin wire 6. Also, the transparent resin sealing member 7 for sealing the leads 3, 4, the chip 5, and the metal thin wire 6 is formed to be used as a lens.
Meanwhile, the electrodes 8, 9 for supplying the power supply to the light emitting diode 2 are provided to the printed circuit board 1. The above leads 3, 4 are inserted into the through holes provided in the printed circuit board 1, and the light emitting diode 2 is fixed/mounted onto the printed circuit board 1 via the solder, etc.
For example, the light irradiating device employing the light emitting diodes is explained in Japanese Patent Application Publication No. H09-252651.
However, since the above light emitting diode 2 is formed as the package into which the resin sealing member 7, the leads 3, 4, etc. are incorporated, there is the drawback such that the size of the packaged substrate 1 is increased. Also, since the radiating characteristic of the substrate itself is inferior, there is the problem such that the temperature rise is brought about as a whole. Therefore, there are the problems such that the temperature rise of the semiconductor chip itself is caused and thus the driving capability is lowered.
In addition, the light emitting diode chip 5 also emits the light from its side surface of the chip. Thus, there exists the light that is directed toward the substrate 1. However, since the substrate 1 is formed of the printed circuit board, there is the problem such that the highly effective emission in which all the lights are emitted upward cannot be achieved.
The present invention has been made in view of the above problems, and can implement a light irradiating device, in which back surfaces of the conduction paths can be connected to the outside to thus eliminate through holes and which has the good radiation characteristic, can be implemented, since there is comprising the steps of preparing a conductive foil and then forming a plurality of electrode forming portions respectively having a plurality of conductive paths by forming isolation trenches, which are shallower than a thickness of the conductive foil, in the conductive foil except at least areas serving as the conductive paths, fixing respective photo semiconductor chips on desired conductive paths of the electrode forming portions, sealing with a resin which can transmit a light to cover the photo semiconductor chips and to fill the isolation trenches, and removing the conductive foil on the side on which the isolation trenches are not provided.
Also, there is provided a light irradiating device manufacturing method that comprises the steps of preparing a conductive foil and then forming a plurality of electrode forming portions respectively having a plurality of conductive paths by forming isolation trenches, which are shallower than a thickness of the conductive foil, in the conductive foil except at least areas serving as the conductive paths, fixing a plurality of photo semiconductor chips onto desired conductive paths of the electrode forming portions, forming connecting member which electrically connects electrodes of each of the photo semiconductor chip and other desired conductive paths, sealing with a resin which can transmit a light to cover the plurality of photo semiconductor chips individually and to fill the isolation trenches, removing the conductive foil on thickness portions on which the isolation trenches are not provided, and separating the photo semiconductor chips into an individual light irradiating device by cutting the areas that are not sealed with the resin. Therefore, the bowing generated when respective light irradiating devices are sealed with the resin can be prevented.
In addition, when the conductive foil is bent to surround at least the areas, to which the photo semiconductor chips are adhered respectively, of the conductive foil, such conductive foil is bent to have an inclination angle that enables the light emitted from the photo semiconductor chip to reflect upwardly. Therefore, the irradiation efficiency can be improved.
Further, the conductive foil is bent by the press machine, etc. in the situation that the corrosion-resistant conductive film is formed on the conductive paths. Therefore, the gloss appears on the conductive film, and thus the irradiation efficiency can be much more improved.
In this case, unless the conductive foil is bent as described above, the surface of the conductive film can be made substantially evenly by applying the pressure to the conductive foil by the press machine, etc. in the situation that the corrosion-resistant conductive film is formed on the conductive paths. Therefore, the gloss appears on the conductive film, and thus the improvement of the irradiation efficiency can be achieved.
Also, there are provided the step of removing the conductive foil on the side, in which the isolation trenches are not provided, up to a predetermined position after the light irradiating devices are covered with the light transparent resin to fill the isolation trenches, and then the step of separating the light irradiating devices that are covered with the light transparent resin. Therefore, respective light irradiating devices are not separated up to the final stage, and accordingly the conductive foil can be provided to respective steps as one sheet, and thus the workability becomes good.
Further, every light irradiating device is individually sealed with the resin by the transfer molding using the mold. Therefore, the generation of the bowing can be suppressed in contrast to the case where the overall conductive foil is sealed. In addition, the workability can be improved and also the proper lens shape can be formed.
Also, in the case that the individual light irradiating devices that are sealed with the light transparent resin are separated by the press machine, the process of removing the flash generated on the end portions of the light irradiating devices is not needed and thus the productivity can be improved.
Further, by using the conductive foil including the slit, the generation of the bowing can be suppressed since the stress-strain is distressed by the slit.
Also, since the arranging positions of the slits are specified not to form the slits at least in the direction intersected with the resin pouring direction, the resin never comes into the back surface of the conductive foil 61 via the slits in the transfer molding using the mold, and thus the workability can be improved.